Raw material iron ore fines are fed to Iron ore grinding system (IOGS – 160 t/h) for grinding the ore to 85% -200 mesh. We use the wet grinding process for this. The slurry produced is then fed to filter press. For pelletisation, we require filter cake of 8.5% to 9% moisture, therefore we are adopting Pressure Filter supplied by M/s Outotec(Larox) from Finland.
Filter Press system is then used to remove the excess water from the slurry to produce filter cakes of approximately 8.5% to 9% moisture. The produced Filter cakes are then transported to the proportioning building by belt conveyor. The raw material, Bentonite and the dust collected in the plant is subjected to automatic weight proportioning with set proportioning ratio according to production requirements.
The proportioned mix is then mixed in vertical mixer supplied by M/s EIRICH from Germany and the mixed proportioned is fed to Balling Disc building (Pelletising). The Balling building is provided with 6 sets of 6 m dia balling disc with 5 in operation and 1 standby. 0.5% to 1.0% water will be added in pelletising process so as to realise optimum value of water content in the mix for pelletising and green pellets are produced.
The green pellets produced are screened by roller screen to screen out (9)mm to (+16) mm grain size and is then distributed onto wide belt conveyor and swing belt conveyor. It is uniformly distributed onto the travelling grate bed which has a specified thickness of 200 mm.
The green pellets are dried and preheated on travelling grate machine (4m width, 48 m Length). The drying process consists of Updraft drying section, Downdraft drying section, Preheating section I and Section II.
The Roasting and solidification process of pellet is done in the rotary kiln(5m dia, 35 m Length) and rolled along the circumference of rotary kiln. Specially designed Powder coal burner is installed at kiln discharge end and the flame length, high temperature position and, air-powdered coal ratio.With heat radiation action inside the kiln, the pellet is roasted at the same time of rolling so as to ensure uniform roasting . The roasting temperature of pellet is 1250 – 1350oC.
The pellets discharged from rotary kiln is about 1250oC and is uniformly distributed on the pellet cart of annular cooler through receiving hopper of annular cooler. The pellet is then cooled to below 100oC and is further oxidised in the annular cooler so that the FeO content is reduced to below 1%.
The discharging hopper of annular cooler discharges the < 100oC finished pellet to finished product belt conveyor and then to product Stock yard through Tripper conveyor.
For De-dusting purpose, Plant De-dusting ESP has been installed. The dust collected is fed pneumatically to a collecting Bin in proportioning building and the same is reused as raw material.